Other than the cheap legacy drop in detachable kit( which does work well, just flimsy-ish plastic), you are going to have to inlet any and all bottom metal kits.
I have a badger ordinance m4 kit in a bell&carlson varminter, remmy 700 short action, 308. Substantial milling required and some bedding (filling).
I just recieved a magpul "bottom metal" (not so flimsy plastic) that i will be in letting in another B&C tactical varmint stock. Not as much meat to come out compared to the badger kit. No where near as robust mind you.
If you are going to do the work, i would suggest a router type guide for your dremel (live and learn on that one). Or if you have a smithy do the work expect a $250-$300 bill.